Insecticidal film-forming composition and method of making same



United States Patent INSECTICIDAL FILM-FORMING COMPOSITION AND METHOD OFMAKING SAME Irwin Hornstein, East Riverdale, Md., and William N.Sullivan, Washington, D. (3,, dedicated to the public No Drawing.Application June 15, 1954, Serial No. 437,015

.15 Claims. (Cl. 167-42) '(Granted-under'Title 35, U. S. Code (1952),sec. 266) cidal compositions of increased effectiveness and durabilitywhich are obtained by preparing a solid solution of lindane or jDDT in asolid film-forming mixture of isomeric chlorinated terphenyls. Thisreproducible chlorinated terphenyl mixture containing 60% chlorine byWeig i commer i lly a ai bl from th M nsan Chemical Company, and isdesignated as Aroclor 5460. Thr ughout the rem inde f th e cription whih f ll ws this material will. be referr d to simply a Arocl r- It hasnow been found that Aroclor is particularly efeo.

tive i in reasing the effectiveness and durabili y of insecticidecoatings in which the active ingredient of such coatings is a relativelyvolatile chlorinated organic insecticide.

Among these volatile organic insecticides are aldrin the majorconstituent of whichi 1.2.3. ,l0,10- ei ach1oro-1,4,4a,.5,8,8a-hexahydro-1;4-endo, .eXo 5, dimethanonaphthalene; hpiachlor whi h is. 1, ,5,6.,7,8.8-h p a- ,7a:tetrahyd -4,7-mthanoindene; and lindane esentially the gamma isomer of1,2,3,4,5,6-hexaehlorocyclohexane Throughout the remainder .of thisdescription these insecticides will. also be. referred to by theirtrivial names, i. e. aldrin, heptachlor, lindane.

These insecticidalmixtures are useful for both indoor andoutdoor-application. When applied indoors; in addition to prolonging theefiectiveness of the insecticide, the unpleasant appearance of a heavy,white, insecticidal deposit is completely avoided; instead. the residueis a practically invisible, transparent solid solution of the pesticidein Aroclor. When applied outdoors, residual deposits remarkablyresistant to weathering are obtained.

The properties of Aroclor that make it uniquely suitable for use withthe volatile chlorinated organic insecticides are as follows: i

(1) It is a film-forming, adherent, water-insoluble, low molecularweight material.

(2) It is an excellent solvent for linclane, aldrin, heptachlor, etc.The insecticide may be present to the extent of 100% the weight ofAroclor.

(3) It is inert, resistant to oxidation, non-fiammable, and does notafford a medium for fungus growth. Once the insecticide-containing filmhas been deposited, and the solvent evaporated, no further change in thephysical properties of the film is to be expected.

(4) Aroclor has an extremely low vapor pressure and its vaporizationrate is negligible.

2,809,147 Patented Oct. 8, 1957 (5) Mixtures. varying from 1:1 to 1:10of insecticide and Aroclor by Weight provides a residual surface that isvery-slightly tacky. Insects walking over such a surface pick up theinsecticide more readily than when they travel across a hard surface.

The insecticides are incorporated into the film by dissolving Aroclorand the insecticide inamutual low-boiling solvent, preferably achlorinated organic solvent such as methylene chloride, methylchloroformor ethylenedichloride or in a ketone such as methylethylketone. Mixturesof this kind can then be applied as a solution or an emulsion bydipping, painting, spraying, as an aerosol, or as a wettable powder ordust.

These compositions are particularly useful in the application ofresidual insecticide coatings to porous surfaces and outdoor foilage.Very concentrated solutions of a mixture of an insecticide such aslindane and Aroclor are prepared by dissolving both in a suitablelow-boiling solvent. This solution may be sprayed using conventionalequipment. Once the particles emerge from the spray nozzle, only a smallamount of solvent can evaporate before a tiny plastic sphere, about 100microns in diameter is formed. The particle size is a function amongother factors of type of nozzle, and pressure, and is thereforecontrollable. This method of application gives excellent dispersion andcoverage. The spheres adhere tenaciously to the surfaces on which theydeposit without penetration. Control of particle size andnon-penetration of insecticide are of extreme importance, andplastic-sphere applications are many.

These new insecticidalmaterials, because of their appearance andresidual effect have a wide variety of application. Some of the manyuses involve control. of larvae and adults of the housefly and mosquito,control of house flies on cattle, Control of household insects inmilitary hospitals and mess halls..

These new materials also give increased persistence to insecticides onfield crops, ornamentals, and outdoor foli ge in general. They are lsouseful as a pesticidal treatment for storage bins and sacks and, becauseof the water insolubility, for the contol of aquatic insects attackingpiers.

EXAMPLES 1.0 part by weight of aldrin and 1.0 part by weight of Aroclorwere dissolved in 6.7 parts by weight of, methylethylketone. Thesolution was applied to pine foliage outdoorsat the rate of 1.8 poundsper acre, After 60 days, house flies exposed to the treated foliagestill showed 100% mortality. 1.0 part by weight of aldrin alonedissolved in 6.7 p rt by Weight of .methyl hylketone and then applied inan identical manner to pine foliage at a rate of 2.1 lbs. per acre gaveonly a 5% .kill against house flies after 10 days.

1.5 parts by weight of lindane and 3.!) parts by weight of Aroclor weredissolved in 150 parts by weight of ethylene dichloride; 20 grams ofthis solution when poured on a one square foot panel of aluminum gave adeposit which after evaporation of the solvent showed no sign ofcrystallization and was a clear transparent film. After days thissurface still gave 66 percent kill against American cockroaches andpercent kill against Japanese beetles. An equal amount of lindane wasineffective after 10 days.

III

Five parts by weight of lindane, 5 parts by weight of Aroclor, 50 partsby weight of methylene chloride and 40 parts by weight of Freon-12(dichlorodifluoromethane) were applied as a pressurized spray.Applications on nonporous and porous surfaces were effective againstAmerican cockroaches, Japanese beetles, and house flies.

. 1.0 part by weight of heptachlor and 1.0 part by weight of Aroclorwere dissolved in 6.7 parts'by weight of methylethylketone. Theinsecticidal 'mixture' was applied to outdoor pine foliage. After 30days house fliesexposed to the treated foliage suffered 100% mortalitywhile heptachlor alone after similar outdoor exposure gave zeromortality.

An emulsion containing an emulsifying agent that read- 11y decomposedafter outdoor application, thus minimizing reemulsification afterrainfall, consists of the following:

35 parts by weight of lindane 35 parts by weight of Aroclor 80 parts byweight of methyl ethyl ketone 100 parts by weight of water /2 part byweight of ammonium oleate After 44 days an initial deposit of 2.0 lbs.per acre gave 96 percent kill against house flies. A standard lindaneemulsion applied in a similar manner after 9 days gave 2 percent kill.

1,000 parts by weight of lindane and 1,000 parts by weight of Aroclorwere dissolved in 1,750 parts by weight of methylethylketone. Thisconcentrated solution was dispersed using a mist-blower in a wind of 20miles per hour. Deposition began 20 feet from the mist-blower, peaked at110 fcet, was 30 percent of peak at 300 feet and there was sufficientdeposit to kill insects at 400 feet. The deposit consisted of smallplastic-like spheres about 100 microns in size that gave excellentdispersion and coverage. This deposit was still giving excellent controlafter one month.

1,000 parts by weight of aldrin and 1,000 parts by wight of Aroclor weredissolved in 3,300 parts by weight of methylchloroform and sprayed outat 50 pounds per square inch pressure. Small plastic-like spheres wereproduced that gave excellent coverage and dispersal. The deposits werestill toxic after one month. The use of this non-flammable solvent is ofparticular value for aircraft spraying.

We claim:

1. An insecticidal composition comprising a chlorinated hydrocarboninsecticide and a film forming chlorinated terphenyl.

2. An insecticidal composition comprising a chlorinated hydrocarboninsecticide, a film forming chlorinated terphenyl, and a solvent.

3. An insecticidal composition comprising a film forming chlorinatedterphenyl and a member of the group consisting of aldrin, lindane, andthe heptachlor. v

4. An insecticidal composition comprising a film form ing chlorinatedterphenyl, a member of the group consisting of aldrin, lindane, andheptachlor and a solvent.

5. An insecticidal composition comprising aldrin and a film formingchlorinated terphenyl.

6. An insecticidal composition comprising lindane and a film formingchlorinated terphenyl.

7. An insecticidal composition comprising heptachlor and a film formingchlorinated terphenyl.

8. The method of claim 15 in which the insecticide is aldrin.

9. The method of claim 15 in which the insecticide is lindane.

10. The method of claim 15 in which the insecticide is heptachlor.

11. A method for producing an insecticide coating of enhanced durabilityand effectiveness on a surface which comprises dissolving a chlorinatedhydrocarbon insecticide and a film forming chlorinated terphenyl in alowboiling organic solvent, coating a surface with the soformedsolution, and then permitting the solvent to evaporate to produce a filmon the surface of a solid solution of the insecticide in the chlorinatedterphenyl.

12. A method for producing an insecticide coating of enhanced durabilityand efiectiveness on a surface which comprises dissolving in alow-boiling organic solvent 8. chlorinated hydrocarbon insecticideselected from the group consisting of aldrin, lindane and heptachlor anda mixture of film forming isomeric chlorinated terphenyls containingabout chlorine by weight, coating a surface with the so-formed solution,and then permitting the solvent to evaporate to produce a film on thesurface of a solid solution of the insecticide in the isomericchlorinated terphenyls.

13. A method for producing an insecticide coating of enhanced durabilityand effectiveness on a surface which comprises dissolving a chlorinatedhydrocarbon insecticide and a film forming chlorinated terphenyl in alowboiling organic solvent and spraying a mist of the soformed solutionat a surface from a distance sutficient to permit a portion of thesolvent to evaporate and form plastic spheres before depositing on thesurface.

14. A method for increasing the effectiveness and durability of depositsof chlorinated hydrocarbon insecticides which comprises incorporatingsaid chlorinated hydrocarbon insecticide in a film-forming chlorinatedterphenyl to form a coating comprising a solid solution of theinsecticide in the chlorinated terphenyl.

15. A method for increasing the effectiveness and durability of depositsof insecticides of the group consisting of aldrin, lindane, andheptachlor which comprises incorporating said insecticide in afilm-forming chlorinated terphenyl to form a coating comprising a solidsolution of the insecticide in the chlorinated terphenyl.

References Cited in the file of this patent UNITED STATES PATENTS OTHERREFERENCES Penning: Ind. and Eng. Chem., pp. 1180-2, vol. 22 (1930).

1. AN INSECTICIDAL COMPOSITION COMPRISING A CHLORINATED HYDROCARBONINSECTICIDE AND A FILM FORMING CHLORINATED TERPHENYL.